AVISTA CORP

SCHEDULE 13E-4

SC 13E4

PROSPECTUS DATED 10-21-98

EX-99.(A)(1)

FORM OF LETTER OF TRANSMITTAL

EX-99.(A)(2)

NOTICE OF GUARANTEED DELIVERY

EX-99.(A)(3)

FORM OF LETTER TO BROKERS

EX-99.(A)(4)

FORM OF LETTER TO CLIENTS

EX-99.(A)(5)

FORM OF 401K PARTICIPANTS LETTER

EX-99.(A)(6)

OPINION OF THELEN REID & PREIST

EX-99.D